Demountable shelving units or storage racks are used to store goods in a wide range of applications, such as warehouses, retail stores, hardware stores, nurseries, produce growers, and the like. Many large wholesale-style chain stores, such as The Home Depot®, Lowes® and COSCO® use a large number of these racks both inside and outside the stores. The demand for demountable shelving units has therefore increased in recent years with the increasing popularity of the wholesale-style chain stores. The shelving units for these stores are designed to carry thousands of pounds and, as a result, are quite heavy. Manufacturing, transporting and assembling the shelving units has therefore developed into in significant business.
In general, there is a continuing need for heavy and light duty shelving units that are easy to assemble quickly without assembly errors. For example, in a conventional shelving unit assembled with a large number of bolts, a common assembly error occurs when the shelves are attached to the upright supports at offset bolt locations resulting in non-square shelf attachment. This is a relatively easy mistake to make because the available bolt holes on the upright supports are close together, making it relatively easy to install a shelf with a bolt hole offset on one or more of the uprights. Non-square shelf attachment weakens the shelving unit and applies undesirable torque forces to the shelf, which can cause a shelf or shelving unit to twist, bend or buckle. In some case, a large rack of shelving units can be installed with multiple bolt location offsets extending across multiple shelf rows and columns, making correction of the assembly errors a tedious and time consuming process.
In addition, the extent to which the shelving units disassemble can present a tradeoff between ease of assembly and convenience for transportation, typically in a container carried by ship or truck. That is, a fully disassembled shelving unit can be stacked most compactly for transport, while maximizing the amount of assembly required once the shelving unit has arrived at its final destination. Shipping the shelving unit with partially assembled structures typically makes the unit assembly easier and faster, but reduces the number of shelving units that can be packed into a shipping container. There is, therefore, a continuing need for shelving units with desirable characteristics for both shipping and on-site assembly at the unit's final destination.